1. Field of the Invention
The present invention relates to an integrally molded air-bag cover article and a method of making the same and, in particular, to an integrally molded air-bag cover article in which an air-bag cover made of a resin is integrally formed with a part of a vehicle interior equipment made of a resin, and a method of making the same.
2. Related Background Art
It has been well known to attach an air-bag device to a vehicle as means for protecting a driver/passenger in case of emergency of the vehicle. When the vehicle receives a sudden impact due to drastic deceleration, stop, or the like, the air bag is filled with a gas so as to rapidly inflate, thereby projecting in front of or a side of the driver/passenger and protecting the driver/passenger against the sudden impact.
In a vehicle such as automobile, for example, the air-bag device is typically disposed behind a vehicle interior equipment such as instrument panel or door trim, and the air-bag cover in this portion is integrated with the vehicle interior equipment for the sake of appearances, such that the air-bag device is apparently unseen.
When such an air-bag cover is integrally formed with a part of the vehicle interior equipment, while it is necessary for the air-bag cover to normally maintain its form as a part of the vehicle interior equipment; the air-bag cover should instantly open when the vehicle receives a sudden impact, allowing the air bag accommodated in the rear side of the vehicle to push the air-bag cover and smoothly unfold.
Accordingly, known is a method in which, in the case where the air-bag cover is integrally formed as a part of the instrument panel, a plurality of through-holes are formed with intervals along the periphery of a portion of the instrument panel (cover-breaking portion) which becomes the air-bag cover such that, in case of emergency, the cover portion is broken from the instrument panel so as to open easily, while seal members for hiding the through-holes are attached to the through-hole portion (Japanese Patent Application Laid-Open No. 4-185551).
Also, in the case where the air-bag cover is integrally formed as a part of a door trim, it has been known to form the peripheral portion of the cover as a thin portion adapted to break (Japanese Patent Application Laid-Open No. 4-283147).
In these conventional methods, however, since a step for forming through-holes in the peripheral portion of the air-bag cover integrally formed with a vehicle interior equipment or making this peripheral portion thinner is necessary in addition to a series of molding steps, the manufacturing process has become complicated, thereby increasing the processing cost. Also, these methods have not yet been sufficient in terms of easiness in fracture strength control and designing of appearances.